For example the command salt web1 apache.signal restart to restart the Apache httpd server specifies the machine web1 as the target and the command will only be run on that one minion.
Similarly when using States, the following top file specifies that only the web1 minion should execute the contents of webserver.sls:
base:
'web1':
- webserver
There are many ways to target individual minions or groups of minions in Salt: